PROJECT SUMMARY: The accelerating U.S. opioid crisis requires urgent scientific and public health action. Maternal perinatal use/abuse is particularly deleterious due to its reverberating intergenerational impact. Though prenatal exposure to opioids and other substances have adverse effects on neurodevelopment, advances in neuroimaging and developmentally-sensitive phenotypic measurement now enable characterization of typical and atypical brain-behavior pathways on an unprecedented scale. Mechanistic study that traces the multi-level determinants and patterns of risk and resilience from the prenatal period through childhood requires a large, national cohort that accounts for regional and racial/ethnic variation. We propose the Brains Begin Before Birth (B4) Midwest Consortium, a partnership of neuroscience, substance use, perinatal mental health and child welfare scientists at Washington University School of Medicine (WUSM) and neuroscience, bioethics, pediatric population health, maternal-fetal and addiction scientists at Northwestern University (NU). Along with scientific complementarity, a strength of this regional Consortium is its ability to leverage the contrasting approaches of Illinois (punitive) and Missouri (non-punitive) to prenatal opioid use, providing an exceptional platform for examining the impact of jurisdictional variations on science and practice. Together, we provide a framework for addressing three major areas of challenge key to a high-quality, representative, national multi-site study: (1) Legal/Ethical: Led by NU bioethics and population health experts, we propose a mixed methods approach to delineating barriers and generating solutions to scientific engagement of opioid using pregnant women from varied jurisdictions; (2) Recruitment/Retention: Led by NU experts in behavioral economics approaches to research participation and WUSM experts in care coordination, child welfare and mobile technology, we use innovative methods to test differential effectiveness of messaging in recruitment materials using eye tracking, and employ novel apps and care coordination methods for retention enhancement; and (3) Imaging/Assessment Methods: Led by neuroscience and substance use experts at WUSM and an NU data scientist, we generate best practices recommendations for an informed protocol via: (i) pilot testing a comprehensive pre-/perinatal maternal substance/mental health protocol; (ii) obtaining feasibility data on MRI scans in neonatal abstinence syndrome, also testing other developmental imaging modalities (e.g., EEG, fNIRS), including in community settings; and (iii) applying state-of-the-art epidemiologic risk prediction methods to extant Consortium data to identify methods and timing of key assessments that provide added predictive value. All activities draw on extensive community stakeholder partnerships. Our central focus is the prenatal-early childhood period, with a framework designed to enable meaningful contributions to consortia including later childhood. Transdisciplinary integration spanning population health to neuroscience is essential to ensure that a large national effort delineating the impact of this pernicious epidemic and corollary risk on health and development of children and families can be fully realized.